[Illustration: One of the strange armoured automobiles or "tanks" with which the British surprised the Germans in September, 1916. Their caterpillar trucks and peculiar form make it possible for them to advance easily over obstructions and trenches.] On the following day, February 15, 1917, the troops of the German Crown Prince achieved a success of some importance. After intense artillery fire they stormed four French lines south of Ripont in the Champagne, on a front of about a mile and a half, gaining ground to a depth of half a mile. They captured twenty-one officers and 837 men of other ranks, and a considerable quantity of war material. On the same date the British carried out a successful raid southeast of Souchez, penetrating enemy positions and taking prisoners. In air combats in different sectors British airmen disposed of nine German machines and lost four of their own. The British made important gains on both banks of the Ancre when in the morning of February 17, 1917, they attacked German positions opposite the villages of Miraumont and Petit Miraumont on a front of about two miles. North of the river a commanding German position on high ground north of Baillescourt Farm was carried on a front of about 1,000 yards. In these operations along the Ancre the British captured 761 prisoners, including twelve officers. During the preliminary bombardment of the German positions a British artillery sergeant slipped out of the trenches with a telephone, and, establishing himself in a shell hole in a forward position, directed the gunfire which shattered the German barbed-wire defenses. The Germans made a courageous attempt to oust the British from their newly won positions on the spur above Baillescourt Farm in the morning of February 18, 1917. Their infantry, advancing in three waves with bodies of supporting troops in the rear, were swept by the concentrated fire of the British artillery. The storm of fire shattered the attack and the German forces were rolled back in confusion. At no point were they able to reach the British lines. During the night the British carried out four successful raids on German positions southwest and northwest of Arras, south of Fauquissart and north of Ypres, during which nineteen prisoners were taken and great damage was wrought to hostile defenses.